first image: "Bart the Fink" is the fifteenth episode of The Simpsons' seventh season.
second image:"Lisa the Skeptic" is the eighth episode of Season 9.
third image:"In Marge We Trust" is the twenty-second episode of The Simpsons' eighth season.
fourth image:"Treehouse of Horror V" is the sixth episode of The Simpsons' sixth season and the fifth episode in the Treehouse of Horror series.
fifth image: "The Cartridge Family" is the fifth episode of The Simpsons' ninth season.
sixth image: "Grade School Confidential" is the nineteenth episode of The Simpsons' eighth season.
seventh image: "$pringfield (Or, How I Learned to Stop Worrying and Love Legalized Gambling)"
eighth image: "Bart the Genius" is the second episode of Season 1.
ninth image:"Lisa's Wedding" is the 19th episode of The Simpsons' sixth season.
tenth image: "Three Men and a Comic Book" is the twenty-first episode of The Simpsons' second season.
eleventh image:"Homer Badman" is the ninth episode of The Simpsons' sixth season.
twelfth image: Space Patrol is the fourteenth Simpsons short and originally aired on The Tracey Ullman Show November 8, 1987.
thirteenth image: "The Last Temptation of Krust" is the fifteenth episode of Season 9.
fourteenth image: "Grade School Confidential" is the nineteenth episode of The Simpsons' eighth season.
fifteenth image: "Treehouse of Horror VII" is the first episode of The Simpsons' eighth season.
sixteenth image: "The Wizard of Evergreen Terrace" is the second episode of Season 10.
seventeenth image: Space Patrol is the fourteenth Simpsons short and originally aired on The Tracey Ullman Show November 8, 1987.
eighteenth image: "The Principal and the Pauper" is the second episode of The Simpsons' ninth season.
nineteenth image: "Treehouse of Horror VII" is the first episode of The Simpsons' eighth season.
twentieth: "Home Sweet Homediddly-Dum-Doodily" is the third episode of The Simpsons' seventh season.
21st image:"Lemon of Troy" is the 24th episode of The Simpsons ' sixth season.
22nd image:"Homer the Great" is the twelfth episode of The Simpsons' sixth season.
23rd image:"Krusty Gets Busted" is the twelfth episode of The Simpsons' first season.
24th image: "Who Shot Mr. Burns? Part two" is the first episode of the seventh season
25th image:"Boy-Scoutz 'n the Hood" is the eighth episode of The Simpsons' fifth season
26th image: "Homer the Smithers" is the 17th episode of The Simpsons' seventh season.
27th image: "Lisa on Ice" is the eighth episode of The Simpsons' sixth season.
28th image: "Bart Carny" is the twelfth episode of The Simpsons' ninth season.
29th image:"The Homer They Fall" is the third episode of The Simpsons' eighth season.
30th image: couldn't find
31st image:"Lisa the Iconoclast" is the sixteenth episode of The Simpsons' seventh season.
32nd image:"Bart Carny" is the twelfth episode of The Simpsons' ninth season.
33rd image: "Realty Bites" is the ninth episode of The Simpsons' ninth season.
34th image: "Grampa vs. Sexual Inadequacy" is the tenth episode of The Simpsons' sixth season.
35th image: "The Springfield Connection" is the 23rd episode in the sixth season.
36th image: "The Last Temptation of Homer" is the ninth episode of The Simpsons' fifth season.
37th image: "Lisa the Simpson" is the seventeenth episode of Season 9.
38th image: "Homer's Odyssey" is the third episode of the first season of The Simpsons.
39th image: couldn't find
40th image: "King-Size Homer" is the seventh episode of The Simpsons' seventh season.